A plate-shaped work piece transporting apparatus disclosed in JP 2002-321820A, for example, is used to carry plate-shaped work pieces such as glass substrates for liquid crystal, and is provided with drive force application means having a drive rotor that applies a drive force in the transporting direction while supporting both end portions of the plate-shaped work piece in a contacting manner. Both end portions of the plate-shaped work piece are supported by the drive force application means in a contacting manner, with the intermediate portion thereof supported by a air-supplying-type support means. Blowing-type support means is also provided. This is provided with numerous air ejection portions provided at a predetermined spacing along the route over which the plate-shaped work piece is transported, and a supply source including a compression pump or the like. The supply source and the air ejection portions are connected by a supply duct such that compressed air from the supply source is distributively supplied to the numerous air ejection portions. The plate-shaped work piece is contactlessly supported by supplying compressed air ejected from the air ejection portions between both end portions of the plate-shaped work piece.
In an apparatus for transporting a plate-shaped work piece in a vertical or near vertical orientation disclosed in JP 2002-308423A, for example, the drive force application means applying drive force in the transporting direction is provided with a drive rotor supporting a lower end portion of the plate-shaped work piece in a contacting manner while applying a drive force. One of the end portions is supported in a contacting manner by the drive force application means, whereas an intermediate portion of the plate-shaped work piece transported in a vertical or near vertical orientation is supported by the air-supplying-type support means. The air-supplying-type support means is provided with numerous air ejection portions at a predetermined spacing along the path over which the plate-shaped work piece is transported, and a supply source including an air blower, for example. The supply source and the air ejection portions are connected by a supply duct such that compressed air from the supply source is distributively supplied to the numerous air ejection portions. Compressed air ejected from the air ejection portions is supplied onto an intermediate portion of the plate-shaped work piece, contactlessly supporting the plate-shaped work piece.
With plate-shaped work piece transporting apparatuses of the prior art described above, when a pulsation occurs in which the amount of compressed air from the supply source occasionally varies, a pulsation also occurs in the compressed air supplied toward the lower surface of the plate-shaped work piece, resulting in the problem that the intermediate portion of the plate-shaped work piece to which the air is supplied moves up and down and a large load is applied to the plate-shaped work piece.
Further, with conventional plate-shaped work piece transporting apparatuses, when the amount of purified air that is supplied is reduced due to some abnormality with the air-supplying-type support means, the transported object drops below the predicted height at which it is supported by the air-supplying-type support means due to the drop in force supporting the transported object, resulting in a high probability that the transported object will come into contact with the air-supplying-type support means positioned below it and either the transported object itself or the air-supplying-type support means will be damaged.
Moreover, with conventional plate-shaped work piece transporting apparatuses, both ends of the transported object are supported in a contacting manner by the drive force application means, and thus when the supporting force of the air-supplying-type support means drops, the intermediate portion of the transported object is lowered and this causes it to bend and become deformed, and there is a high probability that this deformation will damage the transported object This is particularly noticeable when transporting plate-shaped work pieces such as glass substrates for liquid crystal as the transported object.